Apparatus for steering a longwall mineral mining machine

ABSTRACT

The invention relates to apparatus for steering longwall mining machines. The apparatus comprises an electromagnetic-radiation emitter/detector which is mounted on the end of an arm pivotally mounted on the machine. The emitter/detector is located immediately behind the machine&#39;&#39;s rotary cutter and is urged by a hydraulic jack so as to remain close to the roof.

United States Patent 1 1 [11] 3,719,394 Hartley 1 March 6, 1973 1 APPARATUS FOR STEERING A [56] References Cited MINERAL MINING UNITED STATES PATENTS [75] Inventor: Dennis Hartley, BurtonIm Trent 3,019,338 1/1962 Monaghan et a1 ..299/1 X England FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Coal Industry (Patents) Limited, 1,045,874 10/1966 Great Britain ..299/1 1,132,765 11/1968 Great Britain..... London England 1,047,782 11/1966 Great Britain ..299/1 [22] Filed: Jan. 11, 1971 Appl. No.: 105,299

Foreign Application Priority Data Jan. 15, 1970 Great Britain ..01965/70 Field of Search ..299/1 Primary ExaminerErnest R. Purser Attorney-Stevens, Davis, Miller & Mosher [57] ABSTRACT The invention relates to apparatus for steering longwall mining machines. The apparatus comprises an electromagnetic-radiation emitter/detector which is mounted on the end of an arm pivotally mounted on the machine. The emitter/detector is located immediately behind the machines rotary cutter and is urged by a hydraulic jack so as to remain close to the roof.

12 Claims, 6 Drawing Figures APPARATUS FOR STEERING A LONGWALL MINERAL MINING MACHINE This invention relates to a method of, and apparatus for, steering longwall mineral mining machines.

It has already been proposed to mount a combined radiation emitter and detector on a longwall mineral mining machine on the goaf side of the rotary cutter of the machine so that the thickness of roof-mineral beneath the upper interface between the mineral in the seam being won and the overlying stony strata could be monitored and the machine steered accordingly. The monitoring of the thickness of the roofmineral was thus performed along the path of the cut taken previously to the cut currently being taken by the machine.

A disadvantage of the known proposal is that the emitter/detector unit is prone to damage if it struck a roof support member extending into the path of the previous cut.

It is an object of the present invention to provide a method of steering a mineral mining machine which avoids this disadvantage.

According to one aspect of the invention, a method of steering a longwall mineral mining machine comprises monitoring the thickness of roof-mineral by an electromagnetic-radiation emitter/detector which follows the rotary cutter along the path of the cut currently being taken by the machine, maintaining the detector close to the roof of the cut and allowing movement of the emitter/detector relative to the machine.

According to another aspect of the invention apparatus for carrying out the abovemethod comprises an arm adapted at or adjacent one end to carry the emitter/detector and adapted at or adjacent the other end to be mounted on the machine, the construction being such that the emitter/detector can be maintained close to the roof and can move relative to the machine.

Preferably, the arm is adapted to be pivotally mounted on the machine to permit upward and downward movement of the emitter/detector.

However, it is within the scope of the invention for the arm to be adapted to be mounted on a fixed mounting, in which case the emitter/detector would be mounted for upward and downward movement relative to the arm.

The mounting of the emitter/detector on the arm is preferably such as to allow articulation of the emitter/detector relative to the arm, whatever the arrangement for permitting the upward and downward movement of the emitter/detector.

It is further preferred that the construction be such as to allow the emitter/detector to be moved transversely of the direction of travel of the machine so that the emitter/detector can be moved out of the path of the cut currently being taken by the machine. This may be achieved by a hinge which allows at least part of the arm to be swung with the emitter/detector out of the path of the cut currently being taken by the machine.

Preferably, the emitter/detector forms part of an assembly which includes a roof-cavity detector which comprises a member adapted to be biased towards the roof and to cut out operation of the emitter/detector if the member should move upwardly on encountering a roof cavity.

The invention also provides a mineral mining machine comprising the above apparatus.

Three embodiments of apparatus in accordance with the invention and using the method thereof will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a plan of a longwall coalface and of part of a shearer-loader machine which is in position to cut coal from the face and which is provided with a first embodiment of apparatus constructed in accordance with the present invention;

FIG. 2 is a side-elevation of part of the machine shown in FIG. 1 and an elevation of part of the coalface;

FIG. 3 is a plan on a larger scale of a second embodiment of apparatus constructed in accordance with the invention showing an arm of opposite hand to that shown in FIGS. 1 and 2; and

FIG. 4 is a side-elevation of the arm shown in FIG. 3;

FIG. 5 is a plan of a third embodiment of apparatus of the invention showing an arm of the same hand to that shown in FIGS. 1 and 2; and

FIG. 6 is a side elevation of the arm shown in FIG. 5.

In FIGS. 1 and 2, the longwall coalface 10 has a buttock 12 at which the rotary cutter drum 14 of a shearerloader machine 16 is positioned to cut. The roof-surface of coal is shown at 18 and the floor-surface left by the drum 14 is shown at 20 (FIG. 2).

The machine 16 is mounted to slide along a longwall armoured conveyor 22 resting on the floor 20.

The thickness of roof-coal beneath the interface between the roof-coal and the overlying stony strata (not shown) is monitored by a combined radiation emitter and detector 30 which is mounted at one end of an arm 32. The other end of the arm 32 is integral with a segment 34 which is adapted to be bolted to a ring bearing (not shown) pivotable about the axis 36 of rotation of the drum 14.

The arm 32 is rotatable about the shaft on which the drum 14 is mounted so as to be angularly positioned by a hydraulic jack 38 having its piston-rod pivotally connected to another segment 35 also bolted to he ring bearing and its cylinder is pivotally anchored to the machine body at 40.

The emitter and detector 30 is pivotally mounted on the arm 32 at 42 by a resilient bush device (not shown). The detector 30 is safe-guarded against loss by chains, represented diagrammatically at 44, which are slack enough to permit articulation of the detector 30.

A plough (not shown) for cleaning up cut coal from the floor 20 and loading the debris into the conveyor 22 is mounted on an arm 50 secured to the end of the machine body behind the drum 14.

The method of steering the machine 16 is as follows. The machine 16 cuts coal moving from left to right as shown in FIGS. 1 and 2 and the emitter and detector 30 follows closely behind the drum 14 being held against the newly-exposed roof 18 by the jack 38. The emitter and detector 30 monitors the thickness of coal between the roof surface 18 and the interface between the roofcoal and the overlying stony strata (not shown). Should the thickness monitored change by more than a predetermined small amount, the emitter/detector 30 gives a signal which is used to initiate operation of steering jacks (not shown) located between the machine body and the goaf-side mounting shoes (one of which is located at 52, FIG. 2). Should the thickness of roof-coal be monitored as decreasing, for example, the steering jacks would be extended so that the machine would be rolled about an axis extending parallel to and just above the face-side mounting shoes. The drum 14 would thereafter cut a relatively lower floor and on subsequent push-over of the conveyor 22 the conveyor would be relatively lower positioned in the seam and the thickness of roof-coal left would be greater. This form of correction is repeated so as to maintain the thickness of roof-coal left as constant as possible.

The emitter and detector 30 has a cavity-detector which comprises a rod 54 spring-loaded against the roof 18. Should the emitter and detector 30 encounter a cavity in the roof 18, the rod 54 springs up and is arranged to cut out operation of the emitter/detector 30 so that unwanted steering action in response to the transient change in roof-coal thickness is avoided.

Undulations in the roof are accommodated by angular movement of the emitter and detector 30 about its pivot at 42 and if necessary by angular movement of the arm 32 about the axis 36 of the drum 14. Downward arm movement causes fluid to be expelled from the jack 38 through a pressure-relief valve (not shown). Upward movement is accompanied by flow of fluid into the jack from the machine hydraulic supply.

After the cutting run of the machine along the face has been completed, the jack 38 is contracted in response to manual operation of a valve (not shown) so as to lower the arm 30 and move the emitter and detector 30 clear of the roof 18. The machine is then flitted back along the face and the plough on the arm 50 cleans up the floor 20. During flitting the drum 14 is not driven so that it can roll on the roof or floor and does not cut away the steered roof/floor profile.

With the equipment described above the drum 14 cannot be used to cut clearance right to the left-hand end of the coalface and either an advanced heading or separately driven gate-road and/or stable hole must be created.

FIGS. 3 and 4 show a second embodiment of the invention in which the emitter and detector 30 is mounted on arm 60 which is in two parts connected by a hinge pin 62. The two parts can be held in the position shown by a locking pin 64 or the outer part can be swung clockwise (in FIG. 3) about the pin 62 and locked by putting the locking pin 64 through the alternative hole 66.

The arm 60 is integral with half-segment 68 which, with another half-segment 707 forms a bearing locatable about the drum mounting-shaft of the machine 16. The two segments 68, 70 are connectable by bolts 72. The half-segment 70 is connected to the piston-rod of a hydraulic jack 38, the cylinder of which is anchored at 74 on a bracket 76 secured to the machine body.

The method of operation using the equipment shown in FIGS. 3 and 4 is the same during the cutting run from left to right as described above with reference to the first embodiment of the invention. However, the equipment is designed to facilitate cutting by the drum 14 in the last stage of the flitting run, so that the machine can cut its own stable hole to create a fresh buttock against which to cut.

Therefore, before the flitting begins the arm is lowered by the jack 38 and the locking pin 64 is removed. The outer part of the arm is swung clockwise (in FIG. 3) about the pin 62 so that the emitter and detector 30 is out of the path of the drum 14 and the pin 64 is reset in hole 66 to hold the arm in its retracted position.

In a further modification to the equipment shown in FIGS. 3 and 4 the hinge 62 may be located at a position A in H6. 3.

In another modification (not shown), the rod 54 of the switch-detector may be replaced by a hinged arm biased upwardly by a spring.

FIGS. 5 and 6 show a third embodiment of the invention in which the emitter and detector 309 is mounted on an arm which is pivotally connected by a pin 91 to a support bracket 92 secured to a split-ring 98 clamped around the drum mounting shaft of the machine 16.

. As with the previously described second embodiment the arm 90 can pivot horizontally so that the emitter and detector 30 is swung from its normal operating position within the path of the cut currently being won by the drum to a position within the path of a cut previously won by the drum.

The arm 90 can be locked in either of these two positions by means of a link bar 100 pivotally connected by a pin 102 to a hinge bracket 106 which constitutes the adjacent end of the arm 90, and a locking pin 104 which engages in a hole formed in a bracket 105 fixed to the machine body and in one of three holes formed in the link bar 100. In FIG. 5 the locking pin 104 is engaged in the hole most remote from the pin 102 so that the emitter and detector 30 is held in its normal operating position behind the drum. The remaining holes permit the arm 90 to be held in two other alternative positions in which the emitter and detector 30 is located over the conveyor 22.

The end of the arm. 90 adjacent to the pin 91 is formed by the hinge bracket 106 which is pivotally connected to the remainder of the arm 90 by means of a generally horizontal hinge pin 108 which is not coaxial with the drum shaft.

A hydraulic jack 110 located within the arm 90 is pivotally secured at its ends to the arm 90 at 1 l2 and to the hinge bracket 106 and is arranged to pivot the arm 90 about the pin 108 so as to move the emitter and detector 30 upward or downward relative to the machine.

The method of operation using the equipment shown in FIGS. 5 and 6 is similar to that described previously with reference to the second embodiment of the invention.

In another modification (not shown) the emitter and detector is movable upwardly or downwardly relative to the machine by a mounting for the arm other than a pivotai mounting. I

With the method and equipment described above the emitter and detector follows the drum in the newly-cut path and the risk of damage by collision with roof bars in the previous path is eliminated.

I claim:

1. Apparatus for steering a longwall mineral mining machine in a mineral seam, comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine and which is connectable to a machine, means for connecting the arm to a machine and for vertically urging the emitter/detector, and a cavity detector for cutting out the effect of the emitter/detector upon encountering a cavity in the cutting horizon of the machine for avoiding unwanted steering action in response to a transient change associated with such a cavity.

2. The apparatus of claim 1 wherein said means for connecting the arm to a machine and for vertically urging the emitter/detector, comprises a hydraulic jack.

3. The apparatus of claim 2 additionally comprising pivotal mounting means for connecting the arm to a machine.

4. Apparatus for steering a longwall mineral mining machine, comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector first pivotal mounting means adapted to be connected to a machine for supporting the other end of the arm for upward or downward movement of the arm relative to a machine, means which act on the arm such that in operation the emitter/detector is urged towards the roof of the mineral seam, second pivotal mounting means for supporting the arm for horizontal movement of the emitter/detector relative to a machine and a roof cavity detector for cutting out the effect of the emitter/detector upon encountering a cavity in the roof for avoiding unwanted steering action in response to a transient change due to such a roof cavity.

5. The apparatus of claim 4, in which the roof cavity detector comprises a member biased towards the roof for cutting out the effect of the emitter/detector upon upward movement of the member.

6. Apparatus for steering a longwall mineral mining machine in a mineral seam, comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine, said arm being connectable 0 a machine, means for connecting the arm to a machine and urging the emitter/detector vertically towards a boundary of a machine's cutting horizon, pivotal mounting means connecting the emitter/detector to the said one end of the arm, and a cavity detector for cutting out the effect of the emitter/detector upon encountering a cavity in a boundary of a machines cutting horizon for avoiding unwanted steering action in response to a transient change in the condition of said boundary.

7. A mineral mining machine provided with apparatus for steering said machine, said apparatus comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine, a hydraulic jack connecting the arm to the machine and for vertically urging the emitter/detector and a cavity detector for cutting the effect of the emitter/detector on the machines steering upon encountering a cavity in the cutting horizon of the machine.

8. The mineral mining machine of claim 7, in which said apparatus additionally comprises pivotal mounting means connecting the arm to the machine.

9. A mineral mining machine provided with apparatus for steering said machine, said apparatus comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector, first pivotal mounting means connected to the machine and supporting the other end of the arm for upward or downward movement of the arm relative to the machine, means for acting on the arm so that in operation the emitter/detector is urged towards the roof of the mineral seam, second pivotal mounting means supporting the arm for horizontal movement of the emitter/detector relative to the machine and a roof cavity detector for cutting out the effect of the emitter/detector on the machines steering.

10. The mineral mining machine of claim 9, in which the roof cavity detector comprises a member biased towards the roof for cutting out the effect of the emitter/detector upon upward movement of the member.

11. The mineral mining machine of claim 9 in which the roof cavity detector is also carried by said one end of said arm.

12. A mineral mining machine provided with apparatus for steering said machine, said apparatus comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine, means connecting the arm to the machine and urging the emitter/detector vertically towards a boundary of the machines cutting horizon, pivotal mounting means connecting the emitter/detector to said one end of the arm, and a cavity detector for cutting out the effect of the emitter/detector on the machines steering upon encountering a cavity in the boundary of the rnachihines cutting horizon. 

1. Apparatus for steering a longwall mineral mining machine in a mineral seam, comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine and which is connectable to a machine, means for connecting the arm to a machine and for vertically urging the emitter/detector, and a cavity detector for cutting out the effect of the emitter/detector upon encountering a cavity in the cutting horizon of the machine for avoiding unwanted steering action in response to a transient change associated with such a cavity.
 1. Apparatus for steering a longwall mineral mining machine in a mineral seam, comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine and which is connectable to a machine, means for connecting the arm to a machine and for vertically urging the emitter/detector, and a cavity detector for cutting out the effect of the emitter/detector upon encountering a cavity in the cutting horizon of the machine for avoiding unwanted steering action in response to a transient change associated with such a cavity.
 2. The apparatus of claim 1 wherein said means for connecting the arm to a machine and for vertically urging the emitter/detector, comprises a hydraulic jack.
 3. The apparatus of claim 2 additionally comprising pivotal mounting means for connecting the arm to a machine.
 4. Apparatus for steering a longwall mineral mining machine, comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector first pivotal mounting means adapted to be connected to a machine for supporting the other end of the arm for upward or downward movement of the arm relative to a machine, means which act on the arm such that in operation the emitter/detector is urged towards the roof of the mineral seam, second pivotal mounting means for supporting the arm for horizontal movement of the emitter/detector relative to a machine and a roof cavity detector for cutting out the effect of the emitter/detector upon encountering a cavity in the roof for avoiding unwanted steering action in response to a transient change due to such a roof cavity.
 5. The apparatus of claim 4, in which the roof cavity detector comprises a member biased towards the roof for cutting out the effect of the emitter/detector upon upward movement of the member.
 6. Apparatus for steering a longwall mineral mining machine in a mineral seam, comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine, said arm being connectable o a machine, means for connecting the arm to a machine and urging the emitter/detector vertically towards a boundary of a machine''s cutting horizon, pivotal mounting means connecting the emitter/detector to the said one end of the arm, and a cavity detector for cutting out the effect of the emitter/detector upon encountering a cavity in a boundary of a machine''s cutting horizon for avoiding unwanted steering action in response to a transient change in the condition of saId boundary.
 7. A mineral mining machine provided with apparatus for steering said machine, said apparatus comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector for vertical movement relative to the machine, a hydraulic jack connecting the arm to the machine and for vertically urging the emitter/detector and a cavity detector for cutting the effect of the emitter/detector on the machine''s steering upon encountering a cavity in the cutting horizon of the machine.
 8. The mineral mining machine of claim 7, in which said apparatus additionally comprises pivotal mounting means connecting the arm to the machine.
 9. A mineral mining machine provided with apparatus for steering said machine, said apparatus comprising an electromagnetic-radiation emitter/detector, an arm one end of which carries the emitter/detector, first pivotal mounting means connected to the machine and supporting the other end of the arm for upward or downward movement of the arm relative to the machine, means for acting on the arm so that in operation the emitter/detector is urged towards the roof of the mineral seam, second pivotal mounting means supporting the arm for horizontal movement of the emitter/detector relative to the machine and a roof cavity detector for cutting out the effect of the emitter/detector on the machine''s steering.
 10. The mineral mining machine of claim 9, in which the roof cavity detector comprises a member biased towards the roof for cutting out the effect of the emitter/detector upon upward movement of the member.
 11. The mineral mining machine of claim 9 in which the roof cavity detector is also carried by said one end of said arm. 